Recently, an image pickup device usable for stereoscopically viewing a subject by use of a plurality of image pickup optical systems has been practically used for a digital still camera, a digital movie camera, a camera of an endoscope for medical use and the like. Also, a distance measuring device for measuring a distance to a subject (distance measuring subject) by use of parallax between a plurality of image pickup optical systems is used for an inter-vehicle distance measuring system of an automobile, an autofocus system of a camera, and a three-dimensional shape measuring system.
In the above-described image pickup device, a left eye image and a right eye image for stereoscopic viewing are acquired by a pair of image pickup optical system located on the left side and the right side. In the above-described distance measuring device, the distance to the subject is detected by triangulation based on parallax between the left eye image and the right eye image.
The image pickup device and the distance measuring device as described above use two image pickup devices and thus involve problems of a large size and high cost of the device.
In order to solve these problems, an image pickup device for acquiring an image for stereoscopic viewing from a single image pickup optical system has been proposed (Patent Documents 1 and 2).